1. Field of the Invention
The invention relates to a method for determining a highly accurate position of routes and/or objects, in which the routes and/or objects to be recorded are first of all surveyed.
2. Description of the Related Art
In order to create digital maps, it is necessary for the routes which are contained in the map, for example roads or rails, and possibly also objects, for example landmarks, bridges or known buildings, to be first of all surveyed in order to determine their position. The corresponding route or the corresponding object is entered in the map using this position.
In this case, routes are usually surveyed with the aid of appropriately converted vehicles which travel along a route to be surveyed and in the process continuously determine the position with the aid of position-finding systems, in particular satellite position-finding systems. This is known, for example, from the “StreetMapper” project (www.streetmapper.net) or the “ViewCar” project (www.dlr.de/fs/en/desktopdefault.aspx/tabid-1236/1690_read-3256). The individual position-finding points determined are then combined to form a line which is then subsequently entered in the map as a corresponding route. In this case, it is possible to determine, for each point on the line, the position representing the corresponding position of the route at this location.
The procedure is similar when surveying correspondingly real objects which are to be entered in the digital map. A vehicle equipped with 3D laser scanners travels along the route on which the objects to be recorded are situated. In this case, the objects to be recorded are scanned during the journey using the laser scanner, with the result that a 3D representation of the objects on the route can be created.
Another area of application for such techniques is the creation of so-called digital rail maps, in which a particular rail section first of all has to be surveyed in order to be able to determine the position of the track system. Such digital rail maps are used, for example, in construction planning. In this case, a “virtual” path parallel to the actual rail is usually surveyed when surveying the rail section so as not to hinder rail traffic. However, this procedure has the disadvantage that the measured values are usually very inaccurate, which ultimately results in inaccuracies in the digital rail map.
A further disadvantage of the abovementioned procedure is that the routes usually have to be closed to other road users so that the surveying operation can be carried out. In addition, the accuracy of the position determined depends on the accuracy of the position-finding system, with the result that it is usually impossible to increase the accuracy. This ultimately results in the digital maps created in this manner being unsuitable for applications in which an exact and highly accurate indication of the position is important.